Solid state light sources may be utilized to provide white LED light (e.g., perceived as being white or near-white), as has been investigated as potential replacements for white incandescent lamps. A representative example of a white LED lamp includes a package of a blue light emitting diode chip, made of gallium nitride (GaN), coated with a phosphor such as YAG. In such an LED lamp, the blue light emitting diode chip produces an emission with a wavelength of about 450 nm, and the phosphor produces yellow fluorescence with a peak wavelength of about 550 nm on receiving that emission. Part of the blue light emitted from the blue LED chip passes through the phosphor, while part of the blue light emitted from the blue LED chip is absorbed by the phosphor, which becomes excited and emits a yellow light. The part of the blue light that is transmitted through the phosphor is mixed with the yellow light emitted by the phosphor. The viewer perceives the mixture of blue and yellow light as white light. As an alternative to phosphor-converted white light, red, blue, and green (RGB) solid state emitters may be operated in combination to produce light that is perceived as white.
A solid state lighting device may include, for example, an organic or inorganic light emitting diode (“LED”) or a laser. Examples of packages as referenced above are disclosed in U.S. Patent Application Publication Nos. 2005/0269587, 2004/0126913, and 2004/0079957, which are commonly assigned to the same assignee of the present subject matter.
It is known to mount solid state light sources, such as semiconductor light emitting devices, in packages that may provide protection, color enhancement, focusing, and other utilities for light emitted by such sources. One example of a light emitting die package including at least one light emitting device, a molded body, a lead frame including multiple leads, a thermal transfer material, and a lens is disclosed in U.S. Pat. No. 7,456,499, which is commonly assigned to the same assignee of the present subject matter. The molded body is formed around portions of the leadframe and defines an opening on the top side of the device, with the opening surrounding a mounting pad for at least one LED device.
Despite availability of various solid state light packages in the marketplace, need remains for improved packages suitable for solid state illumination applications, to enhance light output performance, enhance thermal performance, improve device reliability, and to promote ease of manufacture.